The screen shot, instructions and video below show the steps to get Audacity to make .mp3 files. One only needs to do this once.
audacity.JPG

Run the Audacity.exe aplication.
Copy the entire Lame folder to your "My Documents".
When you export your first Audacity recording as an MP3 file and save, you will be prompted to locate the lame encoder. Navigate to "My Documents", open the Lame folder, click the Open button and proceed with saving. You will only need to do this the first time you export an MP3.

Video tutorial
The tutorial and directions above cover how to get Audacity to make .mp3 files after being installed from a RIP. If you wished this installed you may write a heat ticket asking for its installation.